Mobile card readers are available for magnetic stripe cards. A user provides a payment card with a magnetic stripe at the point-of-sale to a merchant. The merchant processes the card using a card reader, e.g., the card is swiped on a detachable card reader coupled to a merchant device, which can be a mobile device. A payment request is sent electronically to a credit card processor. The credit card processor routes the payment request to a card network, e.g., Visa or Mastercard, which in turn routes the payment request to the card issuer, e.g., a bank. Assuming the card issuer approves the transaction, the approval is then routed back to the merchant. In the capture stage, the approved transaction is again routed from the merchant to the credit card processor, card network and card issuer, and the payment request can include the cardholder's signature (if appropriate). The capture state can trigger the financial transaction between the card issuer and the merchant, and optionally creates a receipt. There can also be other entities, e.g., the card acquirer, in the route of the transaction. Debit card transactions have a different routing, but also require swiping of the card.